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CITATION

Water Environment Federation. Clarifier Design: WEF Manual of Practice No. FD-8. US: McGraw-Hill Professional, 2005.

Clarifier Design: WEF Manual of Practice No. FD-8

Authors: Water Environment Federation

Published:  October 2005

eISBN: 9780071589222 0071589228 | ISBN: 9780071464161
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  • Contents
  • Preface
  • Chapter 1 Introduction
  • Approach
  • Traditional and Vendor Approaches
  • A Word about Thickening
  • Chapter Descriptions
  • References
  • Chapter 2 Primary Clarifier Design Concepts and Considerations
  • Introduction
  • Performance
  • Process Objective
  • Factors Affecting Performance
  • Case Studies
  • Chemically Enhanced Primary Treatment
  • Design Concepts and Considerations
  • Wastewater Characterization
  • Configuration and Depth
  • Flow Splitting
  • Inlet Design
  • Sludge Collection and Withdrawal
  • Scum Collection and Withdrawal
  • Effluent Discharge
  • Research Needs
  • References
  • Chapter 3 High-Rate and Wet Weather Clarifier Design Concepts and Considerations
  • Introduction
  • Background
  • Current Practice
  • Regulatory Considerations
  • Role of Clarification
  • Role of Storage
  • Methodology
  • Basics—The Science of Design
  • Wastewater Characteristics
  • First Flush
  • Settling Velocities
  • Measurement of Settling Velocity
  • Estimation of Settling Theory
  • Coagulation/Flocculation
  • Plates and Tubes (Lamella[sup(®)]
  • Example 3.1
  • Changes in Suspended Solids Concentration
  • Changes in Temperature
  • Types
  • Conventional Primary Treatment
  • Rerated Conventional Primary Clarification
  • Chemically Enhanced Primary Treatment
  • Retention Treatment Basins
  • Lamella (Plate or Tube) Clarifiers
  • High-Rate Clarification Process
  • Aeration Tank Settling
  • Step-Feed
  • Vortex Separators
  • Case Studies
  • Ballasted Flocculation
  • Combined Storage/Settling Tanks
  • Pilot Testing of High-Rate Clarification
  • Aeration Tank Settling
  • Vortex Separators
  • Process Selection
  • References
  • Chapter 4 Secondary Clarifier Design Concepts and Considerations
  • Introduction
  • Functions of a Final Clarifier
  • Clarifier Configurations
  • Basics—The Science of Design
  • Sedimentation Process
  • Factors Affecting Sludge Settleability
  • Measurement of Sludge Settleability
  • Clarifier Analysis
  • Design Parameters of Importance
  • Hydraulic Considerations
  • Clarifier Performance Enhancements
  • Process Configuration
  • Selectors
  • Foam Control
  • Dissolved Oxygen and Food-to-Microorganism Ratio
  • Chemical Addition
  • Hydraulic Improvements
  • Aeration Tank Settling
  • Miscellaneous Items
  • Special Considerations with Nutrient Removal Sludges
  • Clarifiers Following Fixed-Film Processes
  • Interaction with Other Processes
  • Cost Optimization
  • References
  • Suggested Readings
  • Chapter 5 Tertiary Clarifier Design Concepts and Considerations
  • Introduction
  • Historical Background
  • Current and Future Uses
  • Basics – The Science of Design
  • Particle Characterization
  • Settling Velocities and Overflow Rates
  • Coagulation and Flocculation
  • Coagulants
  • Metal Precipitation
  • Chemical Phosphorus-Removal Processes
  • Design Methods
  • Aluminum
  • Iron
  • Lime
  • Types of Tertiary Clarifiers
  • Existing Facilities
  • Lime Clarification
  • High-Rage Clarification
  • Clarifiers in Series
  • Case Studies
  • Rock Creek Advanced Wastewater Treatment Plant, Hillsboro, Oregon
  • Water Factory 21, Fountain Valley, California
  • Upper Occoquan Sewage Authority (UOSA) Water Reclamation Plant, Centreville, Virginia
  • Iowa Hill Water Reclamation Facility Breckenridge, Colorado
  • Summary
  • References
  • Chapter 6 Mathematical Modeling of Secondary Settling Tanks
  • Introduction
  • General
  • Types of Models
  • The Role of Models
  • Field and Laboratory Support of Models
  • Governing Equations
  • General Equations
  • Drift-Flux Modeling
  • One-Dimensional Models
  • Numerical Methods
  • Commercial Computational Fluid Dynamics Programs
  • Introduction
  • Commercial Programs
  • Advantages and Disadvantages of Commercial Computational Fluid Dynamics Models
  • Applications of Computational Fluid Dynamics Models
  • Application of Computational Fluid Dynamics Models to Primary Settling Tanks
  • Application of Computational Fluid Dynamics Models to Secondary Settling Tanks
  • Guidelines for Selection of Design Features for Clarifiers
  • Practical Example of the Application of Computational Fluid Dynamics Models
  • Circular Clarifiers
  • Limitations and New Directions in Modeling Clarifiers
  • References
  • Suggested Readings
  • Chapter 7 Field Testing
  • Introduction
  • Purpose of Field Testing
  • Initial Steps in Analyzing a Clarifier’s Performance
  • Determining Clarifier Flows
  • Assessing the Biological or Chemical Process Performance
  • Determining Individual Clarifier Effluent Quality
  • Monitoring Blanket Profiles at Selected Locations
  • Observing ETSS Variations
  • Determining Hydraulic Characteristics
  • Flow Curve Test
  • Dye Tracer Test
  • Drogue Current Test
  • Determining Hydraulic Characteristics for Different Conditions
  • Additional Field Tests
  • Vertical Solids Profiles
  • Temperature Profiles
  • Salinity
  • State Point Analysis
  • Relevance to Design
  • Case Studies
  • Circular Clarifiers
  • Rectangular Clarifiers
  • Reference
  • Chapter 8 Circular Clarifiers
  • Introduction
  • Design
  • Inlet Pipe and Ports
  • Pipe Size and Velocities
  • Inlet Geometry
  • Diameter
  • Depth
  • Outlets
  • Interior Baffles
  • Sludge Removal Systems
  • Scrapers
  • Skimming Systems
  • Blanket Level Detection
  • Algae Control
  • Walkways and Platforms
  • Railings and Safety Measures
  • Drains
  • Equipment Selection
  • Drives
  • Materials of Construction
  • Trends and Problems
  • Feed
  • Sludge Removal
  • Skimmers
  • Weirs
  • Depth
  • Blanket Level
  • Internal Baffles
  • Algae Covers
  • Case Studies
  • Hyperion Wastewater Treatment Plant (Los Angeles, California)
  • Denver Metro, Colorado
  • Kenosha, Wisconsin
  • Summary of Advantages and Disadvantages of Various Circular Clarifier Design Features
  • References
  • Suggested Readings
  • Chapter 9 Rectangular Clarifiers
  • Introduction
  • Typical Hydraulic Flow Patterns
  • Longitudinal Flow Tanks
  • Cocurrent, Countercurrent, and Crosscurrent Sludge Removal
  • Transverse Flow Tanks
  • Vertical Flow Tanks
  • Stacked Clarifiers
  • Dimensions of Rectangular Clarifiers
  • Surface Area and Relative Dimensions
  • Length
  • Width
  • Depth
  • Flow Distribution to Multiple Clarifier Units
  • Inlet Conditions and Designs
  • General Inlet Conditions
  • Flow Distribution within the Clarifier
  • Inlet Design
  • Inlet Baffles and Flocculation Zones
  • Location of the Sludge Hopper
  • Influent End Hoppers
  • Effluent End Hoppers
  • Midlength Hoppers
  • Multiple Hopper Locations
  • Sludge Removal Systems
  • Chain-and-Flight Collectors
  • Traveling Bridge Collectors
  • Discussion of Other Considerations in Designing Sludge Removal Systems
  • Outlet Conditions and Effluent Removal
  • Surface Launders
  • End Wall Effect
  • Weir Loading Rates
  • Submerged Launders
  • Removal of Floatables
  • Internal Tank Baffles
  • Solid Baffles
  • Perforated Baffles
  • Sludge Removal with Internal Baffles
  • Stacked Clarifiers
  • Materials of Construction and Equipment Selection
  • Materials of Construction
  • Equipment Selection
  • Case Histories
  • Increase in Length of Rectangular Clarifiers
  • Retrofit of Midlength Hopper Crosscollector to Manifold Suction Header
  • Comparison of Shallow Rectangular Clarifier with Deep Circular Tanks
  • Depth Requirement Study for High-Purity-Oxygen Activated Sludge Clarifiers
  • Conversion of Longitudinal Flow Rectangular Clarifiers to Transverse Flow
  • Summary, Conclusions, and Recommended Research
  • References
  • Chapter 10 Clarifier Performance Monitoring and Control
  • Introduction
  • Key Parameters
  • Primary Clarifiers
  • Secondary Clarifiers
  • Monitoring and Control Equipment and Instrumentation
  • Introduction
  • Monitoring of Clarifier Drive Unit Operation
  • Sludge Concentration and Density Measurement
  • Installation of Solids Analyzers
  • Sludge Blanket Depth Measurement
  • Case Studies
  • Case Study for Activated Sludge Solids Inventory Monitoring—San Jose/Santa Clara Water Pollution Control Plant, California
  • Case Study for Sludge Control Monitoring—Clark County Sanitation District, Las Vegas, Nevada
  • Case Study for Sludge Blanket Depth Monitoring—Lumberton, Texas
  • Case Study for Sludge Blanket Depth Monitoring—Ashbridges Bay Wastewater Treatment Plant, Toronto, Canada
  • References
  • Chapter 11 International Approaches
  • Introduction
  • United Kingdom History and Development of Clarifiers
  • Water Industry Trends and their Effect on Design Practice
  • Process Design
  • Types of Settling Tanks
  • Functions of the Settling Tank
  • Settling Tank Configurations
  • Primary Tank Design
  • Typical United Kingdom Design Parameters
  • Horizontal Flow Tanks
  • Radial Flow Tanks
  • Desludging
  • Cosettlement
  • Odor Control
  • Humus Tank Design
  • Typical United Kingdom Design Criteria
  • Surface Loading
  • Horizontal Flow Tanks
  • Upward Flow Tanks
  • Final Tank Design
  • Typical United Kingdom Design Parameters
  • Settleability Parameters
  • Design of Sludge Scrapers
  • Desludging Settling Tanks
  • Scum Removal
  • Deep Sidewall Depths
  • Parabolic Floors
  • Alternatives
  • Tertiary Treatment
  • Septic Tanks
  • Alternatives to Conventional Clarifiers
  • Single Tank React/Settle
  • Operational Problems
  • Microbial Considerations
  • Diagnosis
  • Common United Kingdom Problems
  • References
  • Chapter 12 Interaction of Clarifiers with Other Facilities
  • Introduction
  • Clarifiers and Wastewater Collection Systems
  • Effect of Wastewater Collection Systems on Clarifier Design
  • Mitigation of Transient Flow Effect on Clarifier Performance
  • Clarifiers and Pretreatment Facilities
  • Effect of Plant Influent Pumping Station Design on Clarifier Performance
  • Effect of Screening Facilities on Clarifier Performance
  • Effect of Grit Removal System Type and Design on Clarifier Performance
  • Clarifiers and Biological Wastewater Treatment
  • Effect of Primary Clarification on Nutrient Removal in Conventional Activated Sludge Systems
  • Use of Primary Clarifiers for Chemical Phosphorus Removal
  • Use of Primary Clarifiers for Solids Prefermentation
  • Secondary Clarifier Design for Enhanced Nutrient Removal
  • Optimization of Clarifiers—Aeration Basin System
  • Interaction with Solids-Handling Facilities
  • Clarifiers and Sludge Thickening
  • Clarifiers and Anaerobic Digestion
  • Clarifier and Aerobic Sludge Digestion
  • Effect of Plant Sidestreams on Clarifier Performance
  • Case Studies
  • Use of Primary Clarifiers for Solids Fermentation and Enhanced Phosphorus Removal
  • Optimization of Clarifiers—Aeration Basin Design
  • References
  • Appendix A: Settling Test Procedure
  • Index